builtin/vector.lua

   1
   2 vector = {}
   3
   4 function vector.new(a, b, c)
   5         v = {x=0, y=0, z=0}
   6         if type(a) == "table" then
   7                 v = {x=a.x, y=a.y, z=a.z}
   8         elseif a and b and c then
   9                 v = {x=a, y=b, z=c}
  10         end
  11         setmetatable(v, {
  12                 __add = vector.add,
  13                 __sub = vector.subtract,
  14                 __mul = vector.multiply,
  15                 __div = vector.divide,
  16                 __umn = function(v) return vector.multiply(v, -1) end,
  17                 __len = vector.length,
  18                 __eq  = vector.equals,
  19         })
  20         return v
  21 end
  22
  23 function vector.equals(a, b)
  24         return a.x == b.x and
  25                a.y == b.y and
  26                a.z == b.z
  27 end
  28
  29 function vector.length(v)
  30         return math.hypot(v.x, math.hypot(v.y, v.z))
  31 end
  32
  33 function vector.normalize(v)
  34         local len = vector.length(v)
  35         if len == 0 then
  36                 return vector.new()
  37         else
  38                 return vector.divide(v, len)
  39         end
  40 end
  41
  42 function vector.round(v)
  43         return {
  44                 x = math.floor(v.x + 0.5),
  45                 y = math.floor(v.y + 0.5),
  46                 z = math.floor(v.z + 0.5)
  47         }
  48 end
  49
  50 function vector.distance(a, b)
  51         local x = a.x - b.x
  52         local y = a.y - b.y
  53         local z = a.z - b.z
  54         return math.hypot(x, math.hypot(y, z))
  55 end
  56
  57 function vector.direction(pos1, pos2)
  58         local x_raw = pos2.x - pos1.x
  59         local y_raw = pos2.y - pos1.y
  60         local z_raw = pos2.z - pos1.z
  61         local x_abs = math.abs(x_raw)
  62         local y_abs = math.abs(y_raw)
  63         local z_abs = math.abs(z_raw)
  64         if x_abs >= y_abs and
  65            x_abs >= z_abs then
  66                 y_raw = y_raw * (1 / x_abs)
  67                 z_raw = z_raw * (1 / x_abs)
  68                 x_raw = x_raw / x_abs
  69         end
  70         if y_abs >= x_abs and
  71            y_abs >= z_abs then
  72                 x_raw = x_raw * (1 / y_abs)
  73                 z_raw = z_raw * (1 / y_abs)
  74                 y_raw = y_raw / y_abs
  75         end
  76         if z_abs >= y_abs and
  77            z_abs >= x_abs then
  78                 x_raw = x_raw * (1 / z_abs)
  79                 y_raw = y_raw * (1 / z_abs)
  80                 z_raw = z_raw / z_abs
  81         end
  82         return {x=x_raw, y=y_raw, z=z_raw}
  83 end
  84
  85
  86 function vector.add(a, b)
  87         if type(b) == "table" then
  88                  return vector.new(
  89                         a.x + b.x,
  90                         a.y + b.y,
  91                         a.z + b.z)
  92         else
  93                 return vector.new(
  94                         a.x + b,
  95                         a.y + b,
  96                         a.z + b)
  97         end
  98 end
  99
 100 function vector.subtract(a, b)
 101         if type(b) == "table" then
 102                 return vector.new(
 103                         a.x - b.x,
 104                         a.y - b.y,
 105                         a.z - b.z)
 106         else
 107                 return vector.new(
 108                         a.x - b,
 109                         a.y - b,
 110                         a.z - b)
 111         end
 112 end
 113
 114 function vector.multiply(a, b)
 115         if type(b) == "table" then
 116                 return vector.new(
 117                         a.x * b.x,
 118                         a.y * b.y,
 119                         a.z * b.z)
 120         else
 121                 return vector.new(
 122                         a.x * b,
 123                         a.y * b,
 124                         a.z * b)
 125         end
 126 end
 127
 128 function vector.divide(a, b)
 129         if type(b) == "table" then
 130                 return vector.new(
 131                         a.x / b.x,
 132                         a.y / b.y,
 133                         a.z / b.z)
 134         else
 135                 return vector.new(
 136                         a.x / b,
 137                         a.y / b,
 138                         a.z / b)
 139         end
 140 end
 141